Decorative textured metallic surfaces

ABSTRACT

PARTIAL FUSION OF A PARTICULATE CHARGE, SOME OR ALL OF WHICH IS METALLIC TO A PREDETERMINED POINT SHORT OF THERMODYNAMIC EQUILIBRIUM, HAS BEEN FOUND TO DEVELOP ESTHETICALLY PLEASING AND ECONOMICAL DECORATIVE SURFACES. BY PROPER SELECTION OF CONSTITUENTS AND OF THEIR PROCESSING, INCLUDING OPTIONAL PROCESSING STEPS AFTER FORMATION OF THE DECORATIVE TOPOGRAPHY, THE SURFACES CAN BE TARNISH   AND CORROSION-RESISTANT. VARIOUS BRONZE COMPOSITIONS PARTICULARLY LEND THEMSELVES TO THIS STATEMENT.

June 26, 1973 Filed Sept. 23. 1970 TEMPERATURE I. SHEINHARTZ 3,741,788

WEIGHT PER CENT ALUMINUM I I 3O 4O 5O 6O 8090 -AL or(AL) 40 5O 6O 7O 8O ATOMIC PER CENT ALUMINUM FIG. I

June 26, SHEINHARTZ DECORATIVE TEXTURED METALLIC SURFACES Filed Sept. 23. 1970 I c Sheets-Sheet 2 AL-Fe WEIGHT PER CENT ALUMINUM IO 20 3O 4O 50 6O 7O 8O 9O I l l I II 1 I l 1 X HEATING REF?) COOLING I I600 o coouue. REF-.3

I400 |390 I300 er- I Q I I I200 I IS in a J \C/ 1 o IIOO I I? if,

I I I I I, I IOOO I I I Q I 900 9l0 I I LU I I I I I g 800 I I Lu I- 2 I I I I l E I I I 6550 Y MAGN.TRANSF\ I I 99I 005} \I I (962 on 600 I I w I 2 I I 500 I I W I I 400 I I I I I IQ l I Z I I 1 I 300 *IE I I I I I I I 0 IO so I00 Fe ATOMIC PER CENT ALUMINUM AL FIG.2

June 26, 1973 l. SHEINHARTZ DECORATIVE TEXTURED METALLIC SURFACES Filed Sept. 23. 1970 6 Sheets-Sheet 4 WEIGHT PER CENT TIN o O O 0 O O O O 4 O O O m 0 O O 0 w M W l 8 6 4 2 Do mmDkdiwmzwk IOO Sn June 26, 1973 sHEINHARTz 3,741,788

DECORATIVE TEXTURED METALLIC SURFACES Filed Sept. 23. 1970 6 Sheets-Sheet 5 f A PREPARAT|ON 0 3- SLURRY OF PART ICLES IN BINDER SOULUTION, 43

"DOCTOR" BLADE, 45

- CHARGE(E.G. MIX SLURRY) AL 0 PARTICLE ,42

B APPLICATION OF AL 44 3'DV CHARGE TO 3 RA E COPPER SUB T T (OR STEEL,ETC.)

A SUBSTRATE,46

c DRY SLURRY A D. HEAT TO MELT AT 42 LEAST SOME OF METAL A a PARTICLES so THEY FLOW, CONTROLLED BY INERT PARTICLES, AND WET SUBSTRATE 3'DV SURFACE T REGlON,48

E. COOL PRiOR TO ALLOY AND TOPOGRAPHICAL EQUILIBRIA F. BRUSH INERT PARTICLES FROM 3DV SURFACE A A W 5. OPTIONALLY TREAT F0 SURFACE IMFROVEMENT E.G.

- HEAT FOR INTERDIFFUSION OXIDIZE FOR COLOR AND/OR TARNlSH-RESISTANCE PATINATE FOR COLOR LACQUER FOR COLOR AND/OR TARNISH RESISTANCE Q ENAMEL FOR COLOR AND/OR TARNISH RESISTANCE Y FIG.5

June 26, 1973 SHEINHARTZ DECORATIVE TEXTURED METALLIC SURFACES Filed Sept. 23. 1970 6 Sheets-Sheet 6 MIXED POWDERS IN ORGANIC AL PARTICLE, 44

COPPER SUBSTRATE 2 E L m 6 M 4 D... m

1 2 MAO L o A 0% r [WWWPQ v A .u O AOQ VAN-M y u om 4 00 w v n o 0 9 \wfiflrw II/I 0 4 a G R M m N E M I O B F R E U B F A 3-DV SURFACE T REGION, 48

S m FR F U A F WHITE AL'RICH AREAS 1 Mir H C. AFTER BRUSHING FIG.6

FIG.7

United States Patent US. Cl. 117-9 22 Claims ABSTRACT OF THE DISCLDSURE Partial fusion of a particulate charge, some or all of which is metallic, to a predetermined point short of thermodynamic equilibrium, has been found to develop esthetically pleasing and economical decorative surfaces.

By proper selection of constituents and of their processing, including optional processing steps after formation of the decorative topography, the surfaces can be tarnish and corrosion-resistant. Various bronze compositions particularly lend themselves to this statement.

INTRODUCTION Rodins bronze sculpture, The Thinker, is a work of art. Melted down to a shapeless mass, its bronze would have little esthetic value and would be worth only the price of its copper and tin as scrap metal. Melted onto a copper or steel substrate, it would form generally amorphous lumps on the substrate and, because of the rather high melting point of statuary bronze, would melt and alloy extensively into the substrate, warping and deteriorating it.

It has been discovered, however, that this same bronze, separated into its constituent copperand tin portions, and intricately programmed to fuse partially together on a substrate such as copper or steel, surprisingly can be controllably molded by the natural forces of viscosity, surface tension, and interfacial energies into infinitely variable and esthetically pleasing, textured bronze surfaces on essentially undeteriorated substrates-provided, as taught by this disclosure: close control is exercised over various critical ranges and limits of constituents elements and of particle sizes; over delicate balances between the inherent non-wettability of certain particles and the partial overcoming of this non-wettability by selected kinds, amounts, and applications of wetting agents; over time and temperature; over furnace atmospheres; over the rates of interditfusion in both liquid and solid states of the constituents; and over many more variables and parameters as will subsequently be set forth in more detail in this specification.

The resulting three-dimensional, variously-textured and colored bronze surface-conveniently referred to as 3- DVis perhaps the ultimate in decorative metal surfaces. Its spectrum of pleasing effects bridges the gap between individual works of art like The Thinker and flat, utilitarian sheets of bronze and copper. Accordingly, 3-DV is both a new art form and a new family of compositions of matter, comprising a great variety of nonequilibrium, but controlled, metallurgical structures possessing commercial value far beyond their material cost.

The great variety of 3-DV metallurgical structures involves where the tremendous heterogeneity of micro and macrostructures, and large amount of porosity, though completely unacceptable by conventional metallurgical standards, would, by most esthetic standards, be judged to give very handsome and unique decorative surfaces. They therefore command much higher prices than the same metal completely homogenized and densified.

3,741,788 Patented June 26, 1973 3-DV accordingly is a controlled mlange of micro and macrostructures generally far from equilibrium composition and metallurgical structure. In general, any point in a 3-DV structure represents one particular instant, frozen in time, between the complete heterogeneity represented by, for example, nine particles of copper clustered about one particle of tin; and the complete homogeneity resulting from the full interdiffusion of the ten particles to form a homogeneous solid solution in a single piece of tin bronze containing w/o copper and 10 w/o tin.

Subsequent sections of this specification teach how to select and how to secure the particular degrees and shapes of non-equilibrium heterogeneity to achieve the handsome, decorative 3-DV structures. Again it is emphasized that, if the decorative 3-DV structures were broughtfor example by prolonged heating at elevated temperatures-close to equilibrium, the three-dimensional features would have been lost, the variegated textures and coloring would have sagged to a uniform dull plateau, and excessive interaction with the substrate would have deteriorated the base metal.

This thermodynamic flat end-point of the beauty of 3-DV is a fairly close analogy to the Universe slowly sinking by the inexorable attrition of entropy into the featureless torpor of one universal energy band. Beauty is more than merely skin deep; it is based on energy differences. 3-DV has thermodynamic energy differences in ample measure but only faithful color photographs, or preferably the 3-'DV articles themselves, can readily convey the esthetic appeal of this novel material.

In some circumstances, however, only a modest decorative effect is appropriate though tarnish and corrosion resistance are much more universally desired. Despite the more dramatic impact of the 3-DV textured surfaces, therefore, it can be noted that a judicious approach to uniformity, reducing the three-dimensional character of 3-DV more closely to a two-dimensional though still variegated (2-DV) surface, may serve the very utilitarian role of a tarnish and corrosion-resistant coating, even though at a considerably diminished decorative level. In subsequent sections of this disclosure, clear expositions will be made how to achieve either 2-DV or 3-DV surfaces. In general, where the teachings apply to both 2-DV and to 3-DV, only the latter will explicitly be mentioned.

Relatively low cost because of continuous mass producibility is another important industrial advantage of 3-DV. Some of the art forms can be produced individually by the expensive, time-consuming techniques of the hand craftsman. An important virtue of the 3-DV processes disclosed in this specification is their massproducibility; each 3-DV process is adapted to continuous, automatic operation, achieving art forms at commodity pricesindividu'ally in each square inch though manufactured economically by the mile.

Thus 3-DV constitutes not only new compositions and structures of heterogeneous metallic material, but also the decorative, tarnish-resistant and corrosion-resistant surfaces to Which the novel 3-DV processes give rise.

STATEMENT OF OBJECTS The general purpose of the invention is to provide an economical process to produce novel, esthetically pleasing, generally tarnish and corrosion-resistant, decorative metal surfaces in mass production. A more specific purpose is to produce such products in copper-base alloys such as tin bronze and aluminum bronze. Another specific purpose is to employ within critical ranges selected values of the thermodynamics, kinetics, and energetics of the materials involved to induce these inherent characteristics to develop naturally unique topographies of 3-dimensionally textured decorative bronze surfaces, unique in the same sense that each pattern of waves in a square hundred yards of sea is different from every other square hundred yards of sea. This unique feature, combined with the pleasing appearance and tarnish and corrosion resistance of bronzeoptionally buttressed by suitable self-generated and/or applied coatingsis designed to meet the many needs for handsome decorative metal at reasonable prices.

Further objects of the invention will become evident by reading the detailed description and examples.

BRIEF DESCRIPTION OF DRAWINGS AND ILLUSTRATIONS In the drawings and illustrations, in order more clearly to set forth the scope and details of the invention, we show both several processes by which the invention can be carried out and several forms of the resulting product.

FIG. 1 is the binary copper-aluminum equilibrium diagram.

FIG. 2 is the binary iron-aluminum equilibrium diagram.

FIG. 3 is the binary copper-tin equilibrium diagram.

FIG. 4 is the binary iron-tin equilibrium diagram.

FIG. 5 is a generalized manufacturing flow chart for 3-DV.

FIG. 6 is a series of schematic cross-section sketches, not to scale, of the intermediate and final products in the 3-DV manufacturing sequence.

FIG. 7 is a partly broken-away, perspective view of another product of the present invention.

SUM MARY STATEMENT It is to be observed that the present invention provides a novel method for producing, in a fashion which lends itself to economical mass production, novel, esthetically pleasing, decor-atively useful metal surfaces, particularly of the bronzes; that these surfaces can optionally be processed to enhance further their inherently good tarnish and corrosion resistance; that these novel metal products, in addition to their novel and outstanding decorative characteristics, can also have some formability as well as appreciable structural strength; and that the novel processes provided by the invention are readily carried out in existing, or generally similar, furnaces and other equipment found in modern copper and brass mills.

Moreover, 'both copper-base and iron-base substrates can be employed, depending upon the end use. Copperbase substrates are indicated when an all-copper product is desired and when the maximum in formability is required. A mild steel substrate offers lowest cost, and higher strength and stiffness. A stainless steel substrate provides stainlessness with lower cost than copper. Finally, the novel proceses of this invention permit eliminating any permanent substrate, giving rise to very attractive solid and open-work filigrees. Both solid and open-work products can be reinforcedstructurally and esthetically-by appliques and wires in a virtually unlimited range of designs. The novel solid and open-work products are useful as such without substrates; additionally, either can be bonded to substrates such as aluminum, zinc, Wood and plastics which would have been damaged or destroyed by the high heating conditions normally employed in the novel processes using higher melting substrates such as copper and steel.

STATEMENT OF SPECIAL ADVANTAGES A special advantage of this invention is that, at relatively low cost and by using standard metal mill equipment, some of the oldest alloys known to history and even to prehistory--tin bronze, for example, is believed by many to have been the first alloy made by man, ushering in the Bronze Age, many millenia ago-can be transformed into uniquely beautiful decorative metal by the hundreds and the thousands of square yards in mass production but with value appreciably in excess of that of raw bronze and with each square inch as uniquely different as one fingerprint from another. On a somewhat lower esthetic, but correspondingly even more utilitarian, level, the novel processes of this invention can be used to produce less textured but equally corrosion-resistant surfaces, rivaling nickel and chromium plated surfaces on mild steel in utility but with characteristic rich, ruddy, golden bronze hues.

A further special advantage of the 3-DV process is its ability to produce products of a form which hitherto have been economically producible only with very ductile and formable materials like copper and mild steel, and yet with abrasion, tarnish, and corrosion resistance hitherto obtainable only with much less form'able materials. This valuable ability derives first from the fact that the 3-DV material is applied late in the processing of a very formable material like copper or steel to final mill product form such as sheet, wire, tubing, etc.; and, second from the fact that the 3-DV material often isand, in many cases, can beconsiderably more highly and complexly alloyed than known wrought materials with the liberating result that the alloy designer is much more free to use higher and/0r multi-element additions to secure better color, and/or abrasion, and/or tarnish and/or corrosion resistance.

Alternatively, 3DV material can be compounded to emphasize formability, for example for applications that require some bending and/or stretching. In general, these 3-DV compositions would tend to be predominantly in the alpha copper solid solutions with more formability than those with considerable concentrations of intermetallic compounds.

Other special advantages of the novel processes and products of the invention will be manifest in reading the specification and claims.

DETAILED DESCRIPTION It was emphasized earlier that 3-DV is characterized by an almost infinite variety of heterogeneous metallurgical structures rather far from equilibrium.

The roles of equilibria, kinetics, and wetting in 3-DV manufacture Several of the major binary equilibria involved in 3- DV manufacture are shown in FIGS. 1 through 4.

Consider FIG. 1, for example, showing the equilibria between copper and aluminum in all proportions from 100 w/o copper and O w/o aluminum to 0 w/o copper and 100 w/o aluminum. Suppose the smooth, square, clean end of a bar of copper was pressed against the similar end of a bar of aluminum and the junction was heated to, say, 500 C. (932 F.). This is below the melting points of both copper and aluminum.

Some aluminum atoms would diffuse into the solid copper; and some of the copper atoms would diffuse into the solid aluminum. After an infinitely long time, the sequence of phases across the interface would be those shown as single-phase fields in FIG. 1, namely:

. alpha copper solid solution gamma-2 intermetallic compound delta intermetallic compound zeta-2 intermetallic compound eta-2 intermetallic compound theta alpha aluminum solid solution show. But it is an essential feature of this invention that molten metal be in wetting contact for a critical length of time with metal at least part of which remains solid whether this be other metal particles or other metal particles and the substrate. This essential feature will be discussed in the next several sections in some detail.

Most basic form of the 3- DV invention The simplest, most fundamental form of 3-DV is a mixture of two kinds of particles supported by a nonwetted substrate. There are several such possibilities, none of which is preferred to the more controllable, previouslyoutlined, 3-DV System comprising, in its essentials, a mixture of low-melting metal particles, higher-melting metal particles, and inert particles. However, to clarify the 3-DV mechanism of formation as much as possible, the following examples of the simplest, two-particle 3- DV systems will briefly be discussed and compared with the preferred Three or More Particle Systems:

(1) Molten metal supplied to the top of a layer of particles of the same metal coarse enough not to melt completely before the molten metal wets, infiltrates, and freezes to solder or braze the unmelted particles together in a 3-DV configuration. In practice, for example, a sheet of thin copper-which could be considered to be a single particlemight be placed on copper particles about A to 4;" in diameter and heated from the top so the sheet melted and infiltrated the particles. The tight control required to melt the overlying sheet but not the underlying paricles is not economical. The same objection applies to a layer of fine copper particles on top of a layer of coarse copper particles.

(2) Molten metal of lower-melting point supplied to the top of particles of a higher-melting metal, for example molten tin to particles of solid copper. The molten tin could be supplied in any suitable way that permitted 7 adequate infiltration of the copper particles, for example molten tin spraying with sufficient superheat onto adequately preheated copper particles, melting of a sheet or particle layer of tin on top of the copper particles by heating from above, etc. However, the control of 3-DV topography thereby is considerably less than when using inert particles as outlined earlier and as will be discussed in detail later in this disclosure.

(3) Same as the first system discussed in this series except the single metal particles can all be of the same size and are mixed with inert particles. In such a system a mixture of a single metal powder and a single inert powder supported on a non-wetted substrate and heated briefly for a critical period of time would melt and flow some of the metal powder into wetting contact with unmelted metal powder particles and into non-wetting contact with the inert particles. By the mechanisms disclosed earlier: the molten metal solders or brazes the unmelted metal particles together; the dispersed, particulate moldwhich the inert particles constitute and which is described in some detail later-shapes the 3-DV topography; the non-wetted substrate supports the composite until it is frozen in its desired non-equilibrium state; and finally the inert particles are brushed away, revealing a 3-DV artifact which might, for example, resemble the one shown in FIG. 6.

To reduce the 3-DV manufacturing process to its simplest form, the foregoing employed a single metal powder. This might be, for example, copper, or aluminum, or zinc, or lead. "Of it might be a single alloy like stainless steel, tin bronze, or aluminum bronze; or a lead alloy such as 94 w/o lead and 6 w/o antimony; or any of the well-known aluminum or zinc-base die casting alloys. From the earlier discussion of the way 3-DV is formed, it will be appreciated that an alloy, melting over a range of temperature, lends itself more readily to the 3-DV process than an elemental metal or eutectic alloy with a sharp melting point.

In fact, the combination of a low-melting metal powder and a high-melting metal powder so widens the critical ranges of time, temperature and other 3-DV manufacturing variables relative to the very narrow range of conditions required to manufacture 3-DV with a single metal powder that the combination is much preferred in most cases. It does, however, clarify the 3-DV concept to note that 3-DV canunder the very close control of time, temperature and direction of heating required to melt only the top portion of the metal particles in the 3-DV charge and have it infiltrate the remainder of the charge-actually be made with only one metal powder and one inert powder.

(4) Preferred, however, is the Three or More Particle 3-DV System, that is at least one low-melting and one higher-melting metal powder plus one inert powder; the use of a wetted substratewhich can be continuous or discontinuous, like the appliques shown in or reinforcingis optional.

(4.1) In a very important special case, the substrate can be considered to be one large particle, and, in the practical case, it is the particle with the higher melting point. An excellent example is that of a 3-DV charge of mixed aluminum and inert particles on a copper substrate. In the sense used in this disclosure, this is a Three-Particle 3DV System: the first particle is aluminum; the second is inert; and the third is the copper substrate.

(5) A somewhat special case overlapping the monometallic 3-DV just discussed in Systems #1 and #3 and the preferred bi and multimetallic 3DV charges outlined in System #4 is afforded by metal powder such as aluminum with a refractory oxide which is insoluble in the molten metal. Melting aluminum particles-particularly those on which a thick oxide coating has been built up, for example by prolonged elevated temperature oxidation and/or anodic oxidationcauses the metallic aluminum to expand more rapidly than the A1 0 skin encapsulating the metallic aluminum so that the skin breaks into particles, releasing the molten aluminum metal but still tending to mold it somewhat analogously to the inert particles of System #4. However, the Al O is wetter to some extent by the aluminum and cannot be brushed out. The result is an inadequate 3-DV topography relative to that obtainable with the preferred Three or More Particle 3-DV System.

Throughout this disclosure and its appended claims, it is to be understood that, although 3-DV is often described in terms of the Three or More Particle System outlined in the preceeding #4, and moreover a wettable substrate is often included in the description for completeness, it is possible to employ simpler, though less controllable and therefore less desirable, systems such as those described in #1, #2, #3 and #5. Wherever applicable, therefore, the term 3-DV is to be construed to cover all the ystems mentioned as well as their equivalents.

Wetting of substrate; non-wetting of inert particles Wetting contact with the substrate is necessary to bond the 3-DV to the substrate by what, in a specialized sense, approximates a soldering or brazing action; to spread the 3-DV over part or all of the substrate surface; and, in those cases where the substrate contributes a metal, for example copper, to the 3-DV coating, to promote solution of solid copper into the molten 3-DV phase.

The study and control of metallic wetting are complex and often obscure, being in some cases more are than science. It is, for example, affected not only by the metal species involved (e.g. copper-antimony wets and spreads more readily on a copper substrate than does copper-tin; copper-zinc, because of the volatility of the zinc, vapordeposits zinc all over a copper substrate) but also by the cleanliness and condition of the substrate (e.g. a dirty or oxide-scaled copper surface is diflicult to wet). Thus fluxes or wetting agents which liquify and thereby facilitate the removal of dirt and oxide scales, can usefully be employed in 3-DV manufacture. We have discovered, for example, that varying the kinds and amounts of fluxes commonly employed in the soldering and brazing trades notably one or more of the halides-affords a useful measure of control over the degree of wetting in 3-DV manufacture. A preferred wetting agent in 3-DV manufacture is ammonium chloride, NH Cl.

Time and temperature are also important determinants of the degree of wetting utilized in a given system. In general, the longer the time and the higher the temperature, the bettter the Wetting and the more extensive the spreading of the molten metal over the surface of the solid metal.

A further important controlling factor in wetting is the composition of the furnace atmosphere, particularly as this affects the oxide coatings on both the substrate and the metallic particles. The preferred atmosphere is very dry hydrogen i.e. a very high H /H O ratio, or a very high ratio of CO/CO Dew point is a convenient index of the dryiness of a hydrogen atmosphere, the lower the dew point the drier the atmosphere and the more reducing it is to metal oxides. For this reason, incidentally, it is desirable that the copper substrate (not necessarily any copper particles) contain no oxygen since otherwise, as well-known to those skilled in the art, the copper will become hydrogen (steam)-embrittled. For tin bronze 3- DV the dew point should be less than about C. (32 F.); for aluminum bronze, it should be less than about 40, preferably less than about 50 C. (58 F.). For some of the more easily reduced oxides, such as those on tin bronze, the atmosphere does not have to be 100 H 80 N /20 H mixture is adequate. Burning city gas, as in conventional copper annealing furnaces, would probably also generate an adequate atmosphere. Incorporating a chloride or fluoride flux in the 3-DV charge usually makes this type furnace suitable for producing 3-DV tin bronze.

Of major importance in 3-DV manufacture is the lower Wettability by the molten metal of the inert particles that are employed. In a sintered carbide, one needs good wetting and bonding of the carbide particles by the matrix metal so the composite will be strong and relatively tough and so the carbide particles are not easily abraded away. In 3-DV manufacture, however, the poorly-wetted, or unwetted, inert particles serve the transitory but key function of establishing the 3DV texture in the molten (e.g. as in the case of molten aluminum on a solid copper substrate) and slushy (e.g. as in the case of molten aluminum wetting copper particles on a copper substrate) stages of the 3DV process; preserving the 3-DV texture during solidification of the 3-DV metal; and, then, like a conventional mold, being readily removable, e.g. by brushing, because of its unwetted, unbonded relationship to the 3-DV metal.

In this sense, the inert particles serve as a dispersed, particulate mold into which the 3-DV composition is cast; indeed, if the inert particles were formed, e.g. by shaping and sintering, into a conventional mold, the 3-DV composition could be conventionally cast into it and, not wetting it, could readily be removed. However, like The Thinker statue,( it would be homogeneous bronze and therefore, for the decorative purposes intended for 3-DV, not as esthetically interesting as a surface of heterogeneous 3-DV, nor as economical, nor available on convenient, low-cost substrates.

Broad applicability of the 3-DV manufacturing priniciple Most of the examples in this 3-DV disclosure involve bronze 3-DV i.e. a copper-base alloy, notably with tin and/or aluminum, because copper and gold are the only colored metals and only with copper can tonnage quantities of useful products with intrinsic colors such as the bronzes be economically manufactured.

The 3-DV manufacturing principle can, however, be applied to the non-colored metals also provided similar conditions of a higherunelting metal (such as silver) and a compatible lower-melting metal (such as, for silver, zinc, cadmium, tin, etc.), a wettable substrate, less wettable inert particles, and other 3-DV requirements are met. Thus one could develop 3-D textures and either accept them in a white metal form, or, to put the V for varicolored in 3-DV, could coat the white metal surfaces by plating (e.g. of copper or gold or of their colored alloys), by vapor deposition, enameling and many other techniques well known to those skilled in the art. Copper-base 3-DV, after all, is a multi-composite material also.

Throughout this specification and claims, therefore, it will be understood that copper-base 3-DV is discussed for illustrative purposes but the teachings and coverage are to be broadly construed.

Copper substrate and copper particles It is useful to distinguish between copper substrate and copper particles in 3-DV manufacture. Referring again to FIG. 1 but now considering typical 3-DV Bronze manufacturing temperatures of 750 C. (1382 F.) to 850 C. (1562 F), it can be seen from FIG. 1 that, upon heating up to 800 C. (l472 R), aluminum would melt at 660 C. (l220 F.) and all mixtures of aluminum and copper from about 24 w/o to 100 w/o aluminum are at least partially molten at 800 C. (1472 F.).

Hence when aluminum particles in contact with clean, or fiuxed, copper in a suitable reducing atmosphere melt, the molten aluminum wets, spreads over the solid copper surfaces, and dissolves some copper in molten solution; moreover, some of the aluminum dissolves in the solid copper. The former (i.e. the molten aluminum dissolving some copper) starts as 100 w/o aluminum, increases its copper content to about 87 w/o (eta-2 liquidus at 800 C.), then dissolves more copper increasing its copper content to about 88 w/o (eta-2 solidus at 800 C.), whereupon-without any temperature change-it becomes solid. The latter (i.e. the molten aluminum dissolving into solid copper) starts as 0 w/o aluminum in solid copper, diffuses in to form a series of intermetallic compoundsbeta, gamma-1, gamma-2, and finally eta-2 where, if there is any aluminum left molten, the eta-2 starts to melt. But, in 3-DV manufacture, there isnt any residual molten aluminum because the object in general is to form golden bronze colored alloys and these are roughly in about the 75 w/o to 95 w/o copper range i.e. the copper content is usually w/o or more. Hence the molten aluminum is quickly soaked up by the solid copper and becomes solid.

Seemingly paradoxically, in fact, as the temperature of a 3-DV charge increases from ambient to 800 C. (1472 F.), the aluminum first melts; then, with the temperature increasing, starts to alloy with the copper; and, while the temperature is still rising, the aluminum alloy solidifies i.e. freezes while being heatedit literally freezes up.

The foregoing emphasizes again both the heterogeneous metallurgical structure of 3-DV and the fact that this structure is, like a snapshot of storm-tossed surf, the frozen record of the 3-D surface of the sea that existed at one instant duirng a lengthy period of time between the onset of a storm and the complete calm that would eventuate.

Selecting that instant for maximum decorative effect by controlling the many variables is the key to successful 3-DV manufacture.

In the case of aluminum powder as the only metallic constituent in the 3-DV charge applied to a copper substrate, the aluminum melts, wets the substrate, spreads, a little on it, and then freezes up.

In the case of a 3-DV charge containing both aluminum powder and copper powder, the aluminum melts, wets the copper particles as well as the copper (or steel) substrate, and then freezes up. If a copper particle is envisioned as a sponge ball on a billiard table (substrate),

the molten aluminum would be analogous to a lacquer sprayed on the ball and table-the lacquer would penetrate part way into the ball and the felt on the table top bonding or brazing them together. If then one horizontally sectioned progressively through the ball until the table was reached the North Pole of the ball would be high in aluminum (and so would be white in color like aluminum); at about the latitude of Washington, D.C. on the copper ball considering it to be a model of the earth, the center of the circular ball cross-section would be red copper fading out to gold just under, and to white at, the edge; similarly at the equator and the latitude of Australia; then appropriately white again at the South Pole and the top surface of the substrate.

A further complexity to be taken into account in manufacturing 3-DV is the fact that, unless some method of internal heating such as microwave energy is employed, heating of the 3-DV charge will start at the outer surface. The 3-DV charge contains low-melting particles such as aluminum and tin. These accordingly melt first at the surface of the charge and then tend to trickle down through the charge, enveloping the generally round copper particles that happen to be present as just described.

If the 3-DV heating time is relatively shorta matter of minutes at temperaturethe low-melting metal does not have time to soak down completely to the substrate and, being metallic white in color, tends to make the highspotsthe North Poles of the earlier analogy--white. Longer heating times permit the low-melting metals both to trickle down towards the substrate and into the solid copper, both of these tendencies contributing to the formation of copper-rich 3-DV and consequently to golden bronze colors.

As noted elsewhere in this disclosure, however, if the substrate is not wetted by the molten phase of the 3-DV charge, the molten phase tends to ball up into globules in fairly regular equidistant.

Thus, referring to the preceding instance, if heating at 800 C. (1472 F.) were continued, the higher-aluminum white areas would gradually change from white, to pale yellow, to gold and finally to a reddish bronze as the copper content increased by solid state interdiifusion. Thus a spectrum of colors on one fixed 3-D topography can be selected from colorless white to reddish copper by controlling the distribution of the metallic species during the molten period and the diffusion time after solidification. In the shortest time periods (typically a few minutes at temperature), there is a tendency for metallic white 3-D surfaces, particularly at the high spots; often at this stage the substrate surface has been coated with so little aluminum that the appearance is one of silvery-white highspots on a red copper or golden bronze background; on"

further heating (typically a few hours at temperature), interdiifusion occurs sufficiently to let the healthy ruddy glow of copper suffuse the entire surface.

All three general classes of color are attractive on a 3-D surface: all-White; silvery on golden bronze; and all-golden bronze. The 3-DV appearance of the last two seem to have wider appeal and therefore greater commercial utility.

While the foregoing discussion used aluminum bronze as an example, tin bronze could have been used equally well except referring to the Cu-Sn binary equilibrium diagram shown in FIG. 3.

Other representative equilibria encountered with steel substrates are shown in FIG. 2 for Fe-Al and in FIG. 20 for Fe-Sn.

Representative 3-DV manufacturing process The flow chart shown in FIG. 5 graphically depicts the sequence of operations followed in manufacturing a typical 3-DV article. FIG. 6 further elucidates the process by showing schematic, cross-sectional sketches of the intermediate and final 3-DV products.

Some of the generalities of the 3-DV manufacturing that their size be no larger than that of the inert particles.

process were given in the introduction section of this dis closure; a brief exposition of some of the major physical factors like wetting and nonwetting which are involved in the 3- DV process was given in the preceding portion of this detailed description section. Following are the details of a representative 3-DV process, referring to FIGS. 5 and 6.

3-DV charge The preferred 3-DV charge is a uniformly blended mixture of at least two powders placed on a wettable substrate to form the Three-Particle System mentioned previously as System #41.

Low melting metal powder(s).-The first essential powder is that of one or more metals melting lower than the substrate. Preferably such metal powders melt considerable lower than does the substrate; preferably, also, the resulting molten phase wets and strongly bonds to the substrate. Alloying in the sense of forming molten solutions, intermetallic compounds, and solid solutions is not essential but is desirable since this tends to impart increased strength, variegated colors and textures, and increased tarnish, corrosion and abrasion resistance. For example, tin and aluminum are preferred low-melting metals for both copper and steel substrates.

The permissible and the preferred sizes of the lowmelting powder particles are to some extent related to the particle sizes of the inert particles as will be discussed in the following paragraphs.

Inert refractory particles-The second essential kind of powder is inert i.e. it forms neither compounds nor solutions with the metal powders, is higher melting, and either is only poorly wetted or is not wetted at all by the molten metal. These characteristics enable the inert powder to function as the dispersed particulate mold for the 3-DV texture referred to earlier.

The aluminum oxide appears to act as a sponge to contain the molten metal and to prevent it from wetting the entire copper surface and thereby degenerating to a 2-DV plateau. Several grades of aluminum oxide have been tested and the best results were obtained with a -mesh, fused white aluminum oxide. Very fine grades of aluminum oxide appear to prevent any wetting since would, for example, be quite feasible to employ inert particles of pea or raisin size i.e.. A-inch to %-inch diameter. In general, however, an inert particle size range within approximately 10 and mesh is preferred for certain effects. The low melting metal powders can be equally as coarse, or even somewhat coarser, than the inert particles so long as good mixing of the inert refractory particles and the metal particles is effected. By good mixing is meant, not necessarily a perfectly uniform distribution of the components, but simply that mixing of the components which gives the desired S-DV topographyin some cases this is best achieved with a non-uniform distribution of the particle components. In the case of a low melting metal such as aluminum and tin, the fact that the metal melts during 3-DV manufacture minimizes the importance of the size of its particles originally added to the charge; in fact, the

aluminum or tin could be added as a sheet of the metal over asuitable distribution of inert particles on the substrate. If metal particles are used it is in general preferred However, they can be considerably finer depending upon the 3-DV texture desired. For example, if a relatively smooth Z-DV surface is desired, finer metal powder should be used, e.g. in the l00 +200 mesh range.

Experiments to elucidate the effects of major processing and charge variables Several 2DV and 3DV plaques made under systematically-varied conditions gave much useful information on the effects of several major controlling variables.

Effects of temperature and substrate on the appearance of 3-DV tin bronze The following describes an interesting series of one common tin bronze 3-DV charge heated for one period of time-l minutes-at four increasing temperatures from 900 C. (1652 F.) to 975 C. (1787 F.); one series being on a copper substrate, and a second series being on a mild steel substrate.

The common tin bronze 3-DV charge was:

Gm. -35 +80 mesh Cu powder 85 20 +35 mesh Sn powder -9o +150 mesh A1 0 powder 35 NH CI 5 This was applied by the process outlined in FIG. 5, the only deliberate variables being temperatures and substrate. The following results were obtained:

Appearance of the 3-DV on copper or steel The foregoing results demonstrate that increasing temperature for a given time increases the coarseness of lacy 3- DV up to the point where most of the 3-DV slumps into Z-DV; also that, under the cited conditions, the mild steel substrate was wetted more thoroughly than the copper substrate and so exhibited a greater tendency to form 2DV rather than to preserve 3-DV.

Incidentally, approximately half of each plaque in Experiment 11 was immersed in a chemical blackening bath before final wire brushing to demonstrate how strikingly this altered the 3-D-V appearance. As noted earlier, such changes can best be seen either in a color photograph or by examining the 3DV sample itself.

2-DV tin bronze.Manufacture affords considerable insight into the effects of time and temperature and other variables. Its charge was:

Gm. -100 +200 mesh Cu powder 50 100 +200 mesh Sn powder 50 90 +150 mesh A1 0 powder 150 NH Cl None The process was that flow-charted in FIG. 5. The temperature was 950 C. (1742 F.) and the time one hour, four times longer than Experiment 11C and 11G at the same temperature. The longer time and finer powder resulted in a relatively smooth 2-DV despite the absence of any fluxing agent like NH Cl.

2DV aluminum bronze.Certain experiments were performed with temperature and type of mechanical finishing as variables. Their common 2-D=V charge was:

Gm. -35 +80 mesh Cu powder 75 +35 mesh Al powder +90 +150 mesh Al O powder NH Cl 5 Each was processed as outlined in FIG. 5 with 15 minutes at temperature.

Certain plaques were treated at 900 C. (1652 F.) and certain plaques were treated at 925 C. (1697 F.). The higher temperature tends to give a smoother 2-DV.

Certain plaques were finished by bufiing with pumice powder; whereas certain plaques were finished by steel wire brushing. The former were seen to have somewhat smoother 2-DV surfaces.

Amount of 3-DV charge.-As would be expected, the greater the charge, the heavier and, usually, the coarser the 3-DV coating. This effect was demonstrated by two experiments with the following charge composition, the latter experiment utilizing a one-third greater quantity of charge than the former experiments greater in quantity. The charge composition and processing conditions for both were:

250 gm.: +20 +35 mesh Al powder gm.: 90 mesh A1 0 powder NH Cl: None H Atmosphere 10 minutes at 975 C. (1787 F.)

Effect of atmosphere-Can be important in some cases. When applying 3-DV to a stainless steel substrate, for example, it is desirable to use rather dry H e.g. with a dew point of about 50 C. (58 F.) or lower, else wetting of the substrate will be poor. The reason for this probably is that the mixed iron-chromium oxide scale normally present on stainless steel surfaces is not reduced if the moisture content of the H is any higher.

On the other hand, A1 0 is not reduced by H to any significant extent at 3-DV manufacturing temperatures up to 1000 C. (1832 F.). Hence if aluminum powder is employed, no conventional atmosphere is really reducing to it and the best one can do is tomake it as non-oxidizing as possible. As a practical matter this means keeping the moisture content low. In fact, the presence of molten aluminum insures a low moisture content provided there is not too much water to cope with because the molten aluminum will react with any water vapor to form A1 0 and H and will continue to do this until all the exposed molten aluminum is oxidized. Reasonably dry H (normally considered reducing) or N (normally considered neutral) furnace atmospheres are therefore satisfactory for aluminum bronze 3DV as well as, of course, tin bronze 3-DV which is less oxidation-prone.

It was found that a neutral N atmosphere functioned similarly to a much more reducing H atmosphere.

Modes of application of 3-DV charge to substrate The 3-DV charge can be applied to the substrate in a number of different ways including:

(1) The simplest way, by doctoring on a layer of mixed powders.

(2) By mixing the powders into a solution of a binder and doctoring, dip-coating, etc. the slurry on as flowcharted in FIG. 5.

(3) Same as #2 except using a thermoplastic binder and extruding or otherwise forming the resulting plastic mass into a sheet; then applying the sheet, or for example designs from it, onto the substrate.

(4) Rolling, spraying, silk-screening, electrostatic patterns on a nonconductive layer applied to the substrate using techniques well-known to those skilled in the art.

FIG. 5.--Presents a fairly generalized flow-chart for a 3-DV manufacturing process. The process is further shown in schematic cross-section in FIG. 6.

In a representative 3-DV experiment, a low melting metal or alloy powder such as tin, aluminum, indium, antimony, etc. was mixed with aluminum oxide powder and an organic binder such as a lacquer or a plastic resin to produce a paste or slurry which could be applied to the surface of copper strip in a predetermined pattern by painting, spraying, dipping, etc. The painted strip was then heated in a protective atmosphere at a temperature above the melting point of the metal powder. The organic binder volatilized and the metal powder melted and adhered to the copper surface. The aluminum oxide powder is inert and apparently acts like a sponge to prevent the molten metal from spreading over the entire copper surface and destroying the original pattern. As soon as the molten metal is deposited on the surface of the copper it starts to diffuse and form an alloy. By controlling the amount of metal that is deposited and the diffusion time, the composition (and color) of the coating can be controlled.

The diffusion process produces a volume increase, resulting in a 3-D textured effect. The coarse residual aluminum oxide powder further influences the texture because the molten metal is prevented from forming a smooth film as has been previously noted.

Typically, the slurry consists of a metal powder, aluminum oxide powder, flux (optional), and an organic binder. Among the materials which have been used successfully as a binder for making the slurries are:

(1) Duco clear lacquer;

(2) Scrink," an oil base, clear silk screen process ink; and,

(3) Polyisobutylene plastic resin.

The Duco lacquer is a quick drying liquid and forms a hard adherent coat. Continuous mixing is necessary while the paste is being used to avoid settling. Scrink is a slower drying material, but the slurry can be fired before complete drying has occurred. The Scrink paste appears to be easier than the lacquer to apply with a brush.

Polyisobutylene (Vistenex from Enjay Chemical) is synthetic rubber and is a thermoplastic resin. It can be dissolved in xylol to any desired viscosity. The metal and ceramic powders can be readily mixed with the viscous solution which is then doctored or cast onto a smooth surface and dried to form a strong, continuous plastic strip. This plastic strip can be cut to any desired shape and positioned on the copper. If the plastic is wetted with xylol, it will adhere to almost any surface like tacky rubber cement. In a production process the loaded plastic strip could be made continuously, the pattern stamped or cut out, and the scrap redissolved in xylol and used over again.

The furnacing operations in Steps D and G of FIG. 5 and involving melting and diffusion have been discussed in detail previously. A number of the optional surface treatments listed in Step G are discussed in the following paragraphs.

Colors in addition to the inherent golden bronze hues have been obtained by oxidizing at elevated temperatures, by various chemical treatments, or other means. Wire brushing, abrading and the use of textured copper substrates have also yielded interesting and commerically valuable visual effects. The alloy coatings are harder than the pure metals and the abrading operation accentuates the 3-DV appearance.

' Thus a very wide range of 3-DV colors and effects has been obtained by heating the coated copper in air or in a slightly less oxidizing atmosphere at temperatures up to 700 C. and quenching in water. By varying the temperature, time at temperature, atmosphere, and quenching rate, followed by wire brushing or burnishing, an almost unlimited range of effects can be obtained because both the composition of the coating, its texture and the pattern itself will influence the final appearance.

Most of the colored finishes described in a well-known publication 1 were tested: two were found to be particularly promising. One, a green, patina-like coating was formed when the sample was made anodic in a sodium W. H. Safranek, Colored Finishes for Copper and Copper Alloys, November 1968, Copper Development Association,

bicarbonate solution. The adherence of this green coating depends to a very great degree on the surface finish. It generally will not adhere to oxidized surfaces but will adhere to clean copper. By combining a preoxidation and burnishing treatment with this green coating, a wide range of effects can be obtained. This green coat is powdery, and will rub off unless it is protected with a lacquer or equivalent coat.

Another satisfactory chemical color was found to be a black molybdenum oxide formed by making the sample cathodic in an ammonium molybdate solution. This black is very adherent and will not rub off. It will, however, darken the alloy surfaces as well as the copper surface. An interesting effect can be obtained by applying both the black and the previously described green colors.

The appearance of all the variegated samples, both metallic and colored, was enhanced by coating with a transparent plastic film, tradenamed Krylon. Many other lacquers would be satisfactory.

Substrate Copper substrates less than 0.010 thick generally warp during the coating operation. This is due to the volume change that occurs during diflusion. Since diffusion is not occurring uniformly over the entire surface, and usually is confined to one side of a sheet, the coating forms a convexity on very thin copper substrates; steel is less affected. The distortion can be minimized by keeping the coatings as thin as possible.

Thicker copper substrates do not warp, but they are quite soft and can be readily bent. Cold rolling will produce a more rigid strip, but some of the textured effect is lost. It may be possible to minimize this by using textured rolls. Incidentally, texturing the sheet prior to applying 3DV has given some very attractive surface effects.

Copper clad steel appears to be a promising substrate material. Samples have been made using 0.005" copper on steel and the final strip was very rigid.

Continuous 3-DV manufacturing process A representative 3-DV manufacturing sequence is described in the following paragraphs. The major raw materials used in making powder-loaded plastic strip are: Vistanex ((Polyisobutylene from En-Jay Chemical Company) dissolved in xylol; MD 13 aluminum powder; and, -mesh alundum.

These specific components are arbitrary and other equivalent commercial materials could be substituted. Almost any thermoplastic resin could be used instead of Vistanex (Polyisobutylene from En-Jay Chemical powder of similar particle size could be used.

The aluminum and the alundum powder are mixed into the Vistanex solution to form a viscous stable slurry that can be doctored in strip form onto wax paper or other substrate, including the 3-DV substrate. The thickness of the strip is controlled by the wetting of the doctor blade and, due to the controlled viscosity, there is no tendency for the slurry to spread after the strip has been formed. The strip is dried under infra-red lamps and is then ready to be used. It is cemented to the copper strip with the paper side up.

The composition and thickness of the plastic strip establish the appearance of the final coating to a controlling degree as indicated by the following tendencies:

(l) Incorporating l-3% of a flux such as ammonium chloride in the plastic sheet results in a smooth, uniform coating. Omitting the ammonium chloride results in a highly textured or nubbly 3DV finish.

(2) Increasing the aluminum content or the thickness of the plastic strip increases the thickness of the smooth coating or the degree of nubblyness of the textured coating. A typical composition would be 250 grams aluminum powder, grams aluminum oxide powder, and grams Vistanex solution (1 part Vistonex to 6 parts xylol); however, wide variations in composition can be tolerated. The thickness after drying is approximately .025".

The aluminum is apparently deposited on the copper strip as soon as melting occurs, but a significantly longer time at an elevated temperature is necessary to develop the gold color forms by diffusion. The nubbly textured aluminum coating forms in a very few minutes at 850 C. (1562 F.) but it still has an aluminum color. Heating for longer periods of time develops any degree of gold color that is desired. Experiments have indicated that, by doing the prolonged heating in a nitrogen atmosphere and controlling the temperature cycle, the coated copper can be placed on end without running. It is therefore possible to apply the initial coating in a continuous furnace with 2-3 minutes at temperature; then the coated copper strip could be wound into a loose coil and reheated in a batchtype furnace for any length of time desired. This sequence permits using existing brass mill equipment and is very economical.

After the initial furnace operation there is a loose powdery residue left on the strip which is readily brushed off. After the final diffusion treatment, a wire brushing or abrading is necessary to form the bright metallic surface.

Heterogeniety of the 3-DV surface region It is characteristics of 3-DV regions to have metallurgically heterogeneous structures as detailed earlier in this section. As noted elsewhere in this disclosure, prolonged heating will cause copper and aluminum atoms to interdiifuse, increasing the copper content of the peak and changing the color towards golden bronze. In general, the tarnish and corrosion-resistance of the bronzes increases With alloy content although this is not an invariable rule since two-phase structures tend to constitute a series of tiny electrolytic cells which accelerate corrosion. But, up to a point, the higher the aluminum and tin contents of bronzes, the better the corrosion resistance; more over, the addition of small amounts (up to a few weight percent) of ternary, quaternary and higher order alloying elements such as, for example, nickel and cobalt, still further increases corrosion and abrassion resistances and related properties. Unfortunately for those attempting to make wrought bronze products, the workability of the bronzes in general decreases with increasing alloy content. Hitherto, therefore, the the better corrosion-resistance of high-alloy bronzes has not been commercially available in mill products such as sheet. By the novel processes of this invention, however, it is possible to achieve both the economy and utility of thin-section mill products such as sheet and the tarnish, corrosion and abrasion resistance of the more highly-alloyed bronzes morever, this is accomplished in the most economical way of, in effect, cladding a lower-cost, more formable base metal after most or all desired forming has been accomplished on it with the more costly, highly-alloyed bronze.

Melange of metallurgical structures has been described in both the introduction and in the earlier portion of this detailed description section. It is a natural consequence of the novel, non-equilibrium processes of this invention which generates the esthetically pleasing 3-DV topographies. It does not lend itself to cleancut characterization in terms of, for example, precise composition ranges. In general, however, it can be said that the range of compositions encompassed within this disclosure is-in terms of binary equilibria such as those outlined in FIGS. 1 through 4 and recognizing that these must be modified by considerations of ternary, quaternary and higher order equilibria plus the previouslyemphasized fact that 3-DV structures typically are far from equilibriumapproximately as follows for any part of a 3-DV structure from the substrate to the top of the 3-DV profile- The preferable range of compositions is between the terminal alpha solid solutions.

16 "The preferable range of compositions is between the substrate terminal solid solution and the intermetallic compound or intermediate solid solution nearest the lower melting element side of the diagram (e.g. in the copperaluminum diagram of FIG. 1, this is the range from, say, 2 w/o aluminum to theta at about 45 w/o aluminum).

Best results are obtained from the range of compositions between the substrate terminal solid solution and the composition approximately at which desirable properties like golden color, corrosion resistance, etc. have largely been lost (e.g. in the copper-aluminum diagram of FIG. 1, this is the range from, say, 5 w/o aluminum to about 25 w/o aluminum).

Refinements, extensions, and uses of the basic Z-DV and 3-DV invention The basic 2-DV/3DV invention disclosed earlier in this specification constitutes a novel, useful, and very broad foundation on which to build a wide range of refinements, extensions and uses of both the 2-DV/3-DV processes and products. A representative selection of these is outlined in the following paragraphs of this section. Where applicable, it will be understood that 2-DV is included whenever 3-DV is mentioned.

Mild steel and stainless steel substrates Mild steel is the lowest-cost metal substrate; it is strong, ductile, and formable; and in the form of welded tubing and strip it is often available at distress prices because of poor surfaces, etc. which would be of no concern in 2-DV and 3-DV products.

The last point emphasizes an important economic advantage of 3-DV, namely the fact that the substrate need not have a perfect surface; in fact, the substrate might even be considered more suitable for S-DV application if its surface had what are usually considered defects such as scratches, gouges and other surface blemishes since the 3-DV might thereby weld or braze better to it.

As noted previously, when a steel substrate is used and a copper-base 3-DV surface is desired, the copper can be supplied as a copper electroplated coating, or copper cladding, 0n the steel; or the copper can be supplied as copper particles in the 3DV charge.

Decorative particles permanently embedded (i.e. wetted and bonded securely) into Z-DV and 3-DV surfaces As noted earlier, inert refractory oxide particles are not at all, or only poorly, wetted by the molten 3-DV charge and so, by manipulating the natural forces of the molten metals own surface tension and viscosity and the interfacial energies of the several components, the inert particles nudge the novel 3-DV compositions ofmatter into the uniquely handsome, varicolored, and textured topographies that characterize 3-DV.

If a portion of these inert particles is replaced by decorative particles which are insoluble in the molten metal but are wetted better by it so they are abraded out of it during the brushing operation, an added novel and esthetically pleasing dimension is given to 3-DV. Thus Mo C particles and/or low-carbon ferrochrome particles, a familiar article of commerce usually containing about 70 w/o chromium, remainder essentially iron and having a very shiny corrosion-resistant surface and being intrinsically hard and abrasion-resistant, can be embedded in a 2-DV or 3-DV surface to add a spangled silvery sheen plus superior tarnish, corrosion and abrasion resistance.

2-DV/3-DV parquetry Parquetry is inlaid woodwork, in geometric forms and usually in contrasting colors, employed in floors and furniture. 2-DV and 3-DV can replace some or all of the wood in parquetry to achieve new and beautiful effects.

3-DV for such applications can first be bonded to a substrate such as plywood before being assembled into wall, furniture, or floor. It can also be bonded directly to the floor by any suitable adhesive well known to those skilled in the art.

It is common practice in forge shops and the like to have a concrete floor into which is set, before the concrete has hardened, square (e.g. 8" x 8") plates of mild steel about A to A thick with turned-down sides as shown in Figure 7, the turned-down portion being embedded in concrete. 3-DV is very attractive, abrasion-resistant, corrosion-resistant, non-slippery, fabricable, etc. It makes excellent floor parquetry (e.g. squares up to 3 feet on a side; rectangles up to 3 feet wide and as many feet long as desired i.e. deliver coil of sheet to job, unwind and bend sides down, and embed in concrete, etc.), floor tiles and wall tiles for kitchens, bathrooms, etc.

Uses of ferromagnetic properties of 3- DV substrates of mild steel and of ferritic stainless steel Unlike 3-DV on a copper substrate--or a plastic or ceramic material, the use of a mild steel, or ferritic stainless steel substrate makes the 3-DV composite ferromagnetic. Hence one can use this property to hold throw rugs, furniture, pictures and drapes, etc. by equipping the latter with small, flat magnets.

3-DV without a substrate There are important reasons why, for some applications, it is desirable not to have the 3-DV brazed to a substrate such as a copper or steel sheet. E.g. a copper backing may, in an environment corrosive to copper but not to 3-DV, corrode and cause green stains to form on whatever is supporting the 3-DV piece. Similarly a mild steel backing may rust and cause red staining. Or it may be desired to have a 3-DV surface on a ceramic plastic, or low-melting metal. The reducing atmosphere required to form 3-DV is damaging to many ceramics and it may be better to form 3-DV without a substrate and bond it to the ceramic, plastic, or low-melting metal with a suitable adhesive such as are well-known to those skilled in the art. Alternatively, as previously disclosed, 3-DV can be formed on a steel or copper substrate and the composite can then often be bonded to the substrate unless the aforementioned staining might be a problem.

One way to form 3-DV without a substrate would be to use as thin mild steel as possible, then chemically dissolve the mild steel away from the 3-DV which then could be used as a sheet or strip or could be mounted on a corrosion-resistant substrate like wood, fabric, plastic, concrete, etc.

Another way is to form 3DV on a substrate like graphite which the molten 3- DV does not wet. In one variation of this procedure the 3-DV powder charge is placed directly on the graphite and fired. Interestingly, the globules strewn fairly regularly over the 3-DV surface rather like raindrops on an unclean windowpane which they do not wet, form for the same reason the raindrops do not spread into a continuous film of water on the windowpane, namely neither wets the substrate. If the substrate were clean copper or steel, the globules when molten would wet the substrate and spread out on it, leaving only the 3-DV mesh.

In another variation utilizing a non-wetted substrate, the 3-DV powders are placed on top of copper or steel appliques and/ or wires, enhancing both the strength and the beauty of the resulting 3-DV composite.

Composite 3-DV steel sections Particularly for the decorative applications for which 3-DV is so well adapted, only the surface need be decora tive, the substructure often advantageously being made of a lower-cost, more-available material which often has other advantages such as higher strength, stilfness and formability. This is particularly true of 3-DV on either mild or stainless steel, especially the former.

A good example of this is a T section in which the horizontal strip is 3-DV on e.g. a steel substrate, and the vertical strip is mild steel, optionally galvanized or otherwise suitably coated for corrosion protection. Lengths of such sections are lower in cost than an all-bronze similar section, yet are more decorative. The strip sections of the T or similar L, H, etc. sections can readily be joined together by such well-established techniques as electron beam and high-frequency resistance welding.

Another good example of a composite S-DV/ steel section is that of round, square, or rectangular tubing.

Depending upon the economies and application of the particular part, the 3-DV coating could be applied to the steel surface before or after tube forming from a strip in the case of welded tubing; or to seamless tubing in the form. The substrate could, of course, be of any other suitable material e.g. copper.

One particularly useful form of composite tubing would be a 2-DV surface on either inside or outside of the tube wall e.g. mild steel inside tube surface'in contact with Freon refrigerant liquid and ZXDV tin bronze surface on the outside in contact with brakish water in a heat exchanger tube. Another advantageous heat exchanger tube combination is a copper tube with 2-DV aluminum bronze on the outside.

Simulated 3-DV surfaces Wood grain has been simulated in plastics and fiber glass, and S-DV appearance could similarly be approximated. The simulated product would not, of course, have the strength, ductility, abrasion resistance, heat resistance and other metallic properties of true 3-DV bronze. But it could have low weight, low cost, injection moldability, and other attributes of resinous materials.

Accordingly, selected 3-DV topographies could be transferred to die steel mold surfaces by any of the several established techniques well known to those skilled in the art.

Oxide films on 3-DV surfaces The oxide film on aluminum bronze is the barrier to corrosion--the more perfect (point defect-free), stressfree, crack-free, impervious, impermeable, and inert, the better the corrosion resistance. Aluminum bronze chemistry, conditions of film formation, etc. constitute a wide number of variables. Among the variables to work with are low partial pressure of oxygen during heating of an aluminum bronze will tend to give a A1 0 coating since any Cu O that happens to form would be reduced by aluminum diffusing over to it. Introduction of H 0 or 0 during the latter part of the surface interdiifusion would accomplish this.

Spinel skins of the MO-M 0 type (where M represents a metal) are well known for their superior stability and corrosion resistance (e.g. MgO-Cr O on chromium). The M 0 is furnished by aluminum in aluminum bronze. For the MO, candidates include Fe, Ni, Mg, Be, etc. 1% or less is all that is required of these elements.

Heat treatment of the interdiifused layer could be of controlling importance. In the copper-aluminum system, above about 8 w/o aluminum, beta is formed above 565 C. (1049 F.) and, unless cooled rapidly through 565 C. ('1049 R), eutectoidally decomposes to alpha and gamma 2, a combination which is not very corrosion resistant. But rapid cooling suppresses eutectoid decomposition and corrosion resistance increases with aluminum content.

Galvanic Protection of iron by zinc is very well known-the zinc corrodes (to a generally unobjectionable, soft, white ZnO which washes away readily) and prevents corrosion of the iron so long as there is some zinc in contact with the iron at least within an inch or so of the potential corrosion site of the iron. Millions of tons of galvanized steel strip are therefore sold each year. Zinc is a desirable constituent of some 3-DV surfaces so one of the lowest-cost 3-DV surfaces is one formed on galvanized steel. It is also advantageous in some cases to have a zinc layer on the underside of a 3-DV composite. The zinc would tend to go into solution, thereby tending to prevent both the iron and the 3-DV surfaces from corroding or tarnishing.

Defense in depth against tarnishing and corrosion The goal of a truly stainless, decorative, tonnage metal in the sense of one whose original appearance would remain unchanged for decades under both interior and exterior ambient conditions is one which has long been sought. 3-DV, exercising all its options to set up a multiple defense in depth against tarnishing and corrosion, offers an approach to this hitherto unattained goal. As noted throughout this disclosure, these options include various combinations, including all, of the following:

(1) An inherently corrosion resistant substrate e.g. a copper, bronze, nickel silver, cupronickel, Monel or other corrosion-resistant copper-base, or stainless steel, substrate.

(2) A still more corrosion resistant overlay of 3-DV material with a higher concentration of conventional alloying elements such as aluminum and tin in the bronzes; optionally plus special alloying elements such as iron, nickel, cobalt, beryllium, etc.; also optionally heat treated for maximum tarnish and corrosion resistance.

(3) Selective oxidation to develop an especially tarnish and corrosion-resistant oxide surface layer.

(4) Galvanic protection e.g. by an aluminum, zinc or other electropositive metal with inconspicuous corrosion products on the underside of the substrate.

(5) Transparent coating(s) including lacquers, glasses, enamels, etc.

(6) Very thin gold-base alloy coated on the 3-DV by electroplating, vapor deposition or other known means.

(7) Patination by various known chemical treatments.

EXAMPLES In order to elucidate the teachings of this invention more specifically, the following additional examples of the practice of the invention are given.

EXAMPLE 1 A 3DV plaque was made as follows:

the details section.

EXAMPLE 2a A 3-DV plaque was made as follows: 3-DV charge:

300 grams +20 +35 mesh Al powder 100 grams 90 +150 mesh A1 0 powder 125 ml. polyisobutylene Substrate: Copper Process: Essentially as outlined in FIGS. 5 and 6 with following specifics- .150" thick. 10 minutes at 927 C. (1700 F.).

Interditfused 1 hour at 871 C. (1600 F.).

20 EXAMPLE 2b A 3-DV plaque was made as follows: 3-DV charge:

250 grams 20 +35 mesh A1 powder 100 grams ---90 +150 mesh A1 0 powder 100 ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics- Interditfused 2 hours at 927 C. (1600" F.). Oxidized in salt bath. Wire brushed.

EXAMPLE 3 EXAMPLE 4 EXAMPLE 5 A 3-DV cylinder was made as follows: 3-DV charge:

50 grams 35 {+90 mesh Cu powder 50 grams ---100 +200 mesh Cu powder- 15 grams -100 +200 mesh Sn powder 35 grams --90 +150 mesh A1 0 powder 10 grams NH Cl 50 ml. polyisobutylene Substrate: Mild steel Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics- 0.100" thick.

30 minutes at 399 C. (750 F.). Interdiffused 10 minutes at 1004 C. Wire brushed.

EXAMPLE 6 A 3-DV plaque was made as follows: 3-DV charge:

grams --35 mesh Cu powder 15 grams +200 mesh Sn powder 35 grams 90 mesh A1 0 powder 5 grams NH Cl 50 ml. polyisobutylene Substrate: Graphic (therefore unwetted and not part of final plaque).

21 Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics- 0.150 thick. 10 minutes at 982 C. (1800 F.).

Example 7a A 3-DV plaque was made as follows:

3DV charge:

85 grams -35 +90mesh Cu powder 15 grams 100 +200 mesh Sn powder 35 grams -90 +150mesh A1 powder grams NI-I Cl 50 ml. polyisobutylene Substrate: Copper 7 Essentially as outlined in FIGS. 5 and 6 with following specifics .125" thick. 7 p v Patinated by anodic treatment in sodium bicarbonate solution per Safranek, referenced in the details section.

Example 7b A 3-DV plaque was made as follows:

3-DV charge:

85 grams +35. +90 mesh Cu powder 15 grams -100 +200 mesh Sn powder 35 grams -90 +150mesh A1 0 powder 5 grams NH Cl 50 ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5: and 6 with following specificsminutes at 982C. (1800" F.).

Blackened with a commercial brass blackener. Wire brushed. I 1

Example 8 Several 3-DV plaques were made as follows: 3DV charge: 1 v 85 grams ---35 +90 mesh Cu powder grams l00 +200mesh Sn powder 35 grams -90'+150 mesh A1 0 powder 5 grams NH Cl I 50 ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics- I 0.100" thick. v 10 minutes at 982 C. (1800 F.).

Examples 9a and 9b Several 3-DV plaques were made as follows:

3-DV charge:

85 grams 35 +90 mesh Cu powder 15 grams 100 +2.00 mesh Sn powder 35 grams --90 +100 mesh A1 0 powder 5 grams NH4C1 50 ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics 0.150" thick. Copper leaf applique positioned in or over plastic sheet. 10 minutes at 982 C. (1800 F). Blackened with a commercial brass blackener. Wire brushed.

22 Example 10 A 3-DV plaque was made as follows:

.3- ch .7 v V v grams 35 mesh Cu powder 15 grams +200 mesh Sn powder 35 grams -90 mesh A1 0 powder 5 grams NH CI SO-ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5 and ing specifics 0.150" thick.

10 minutes at 982 C. (l80. 0 F.). Glass enamel frit sprinkled over surface. Interdilfused 3 minutes at 816 C. (1500 F.). Light wire brushing.

6 with 011....

Examples 11a through 11d Four 3-DV plaques were each produced on a copper substrate using the following commonmanufacturing process:

Examples 11c through 11h Four 3- DV plaques were each produced on a steel substrate using the following common manufacturing process:

3DV charge:

85 grams 35 +90 mesh Cu powder v15 grams -20 +100 mesh Sn powder 35 grams 90 +150 mesh Al O powder 5 grams NH4C]. Process: I

Essentially as outlined in FIGS. 5 and 6 with following specifics- All four samples were heated for 15 minutes, but each at the following different temperature:

11e-900 C. (1652 F.) 11fi9-25 C. (1697 F.) 11g950 C. (1742 F.) 11h975 C. (1787 F.) Half of plaque dipped in commercial brass blackener. Wire brushed.

Examples 12a and 1213 Two 3-DV plaques were made as follows: 3-DV charge:

75 grams 35 +100 mesh Cu powder 25 grams 35 ;+90 mesh Al powder 35 grams 90 +150 mesh A1 0 powder 5 grams NH C1 Substrate: Copper Process: Process:

Essentially as outlined in FIGS. and 6 with fol- Essentially as outlined in FIGS. 5 and 6 with following specifics-- lowing specifics- Both samples were heated for 15 minutes, but 15 minutes at 900 C. (1652 F.).

each at the following different temperature: 5 Nitrogen atmosphere.

12a-925 C. (1697 F.) 1213-900" (3. (1652 F.) Example 13d Hydrogen atmosphere- A 3-DV plaque was made as follows: Polished. 3-DV charge:

E l 12 250 grams -35 +90 mesh Al powder 100 grams 90 +150 mesh A1 0 powder A 3-DV plaque was made as follows: 75 polyisobutylene 343V charge: Substrate: Copper 50 grams 100 +200 mesh Cu powder Process: I 50 mmesh Sn powder Essentially as outlined in FIGS. 5 and 6 with fol- 150 grams 90 +150 mesh A1 0 powder 5 gramsNH Cl 150 ml. polyisobutylene Substrate: Copper Process: Example 13c ig g g x gggf m FIGS 5 and 6 wlth fol A 3-DV plaque was made as follows:

lowing specifics- 10 minutes at 975 C. (1787 F.) Hydrogen atmosphere.

o a 3-DV charge: 1,593 950 (1742 50 grams 35 +90 mesh Cu powder I 50 grams -35 +90 mesh Al powder Examples 12d and 12e 50 grams 90 +100 mesh A1 0 powder Two 3-DV plaques were made as follows: 150 Polylsobutylene Substrate: Copper 3 DV charge. Process 75 grams 35 +100 mesh Cu powder 25 grams 35:+90meShA1powder Essgnt glly as gutlmed in FIGS. 5 and 6 with fol. grams 90 +150 mesh A1 0 powder 23 c (17870 F 5gramsNH Cl Hdontoh' Substrate: Copper y r ge m Sp Process: Example 13f Essentially as outlined in FIGS. 5 and 6 with following 5pecifics A 3-DV plaque was made as follows:

Both samples were heated for 15 minutes, but 3-DV charg each at the following different temperature: 50 grams +90me5hA1P0Wder 12d--925 C. (1697 F.) 50 grams --90 +150 mesh A1 0 powder 12e--900 C. (1652' F.) v 40 150 ml. polyisobutylene Hydrogen atmosphere. Substrate: PP

Wire brushed' Proctizss: t' 11 S n1 7 d FIGS 6 h r 1 ssen 1a y as ou ne lIl 5 and wit 0- Example lowing specifics- A 3-DV plaque was made as follows: 15 minutes at 900 C. (1652 F.). 3-DV charge: Nitrogen atmosphere.

250 grams 35 +90 mesh Al powder 100 grams -90 +150 mesh A1 0 powder p 14 100 ml. polyisobutylene A 3-DV filigree was made as follows: Substrate: Copper Process: 3-DV charge:

Essentially as outlined in FIGS. 5 and 6with fol- 85 grams -35 +100 mesh Cu powder lowing specifics 15 grams -l00 +200 mesh Sn powder 10 minutes at 975 C. (1787 F.) 35 grams -90 +150 mesh A1 0 powder Hydrogen atmosphere. 5 grams NH Cl 50 ml. polyisobutylene Example 13b Substrate: Graphite (therefore unwetted and not part of A 3-DV plaque was made as follows: 1 fin l p1aque) 3-DV charge: Process:

75 grams esh Al powder Essentially as outlined in FIGS. 5 and 6 with follow- 50 grams -9( +150 mesh Al O powder ing specifics- 175 ml. polyisobutylene Mixture spread over 12 gage deoxidized copper Substrate: Copper wires supported on a graphite (unwetted) sub- Process: strate.

Essentially as outlined in FIGS. 5 and .6 with fol- 15 minutes at 982 C. (1800 F lowing specifics- Blackened with a commercial brass blackener.

15 minutes at 950 C. (1742.F.) Wire brushed. Hydrogen atmosphere.

xam e 1 The wires can be considered either as reinforcing elements, P or as the internal substrate, of the 3-DV material. The A 3 v plaque was d as f ll latter is seen to distribute itself interestingly on the wires 3 h in accordance with the natural consequences of the semi- 50 grams -35 mesh Al powder molten (slushy) 3-DV charge wetting the copper wires 50 grams 90 mesh A1 0 powder and not wetting the interspersed inert A1 0 particles:

ml. polyisobutylene where a length of wire is distant an inch or so from an Substrate: Copper 75 adjacent wire, the tin bronze tends to ball up in large globules reminiscent of the raindrop globules; where the wetted Wires are closer together, sufiicient metal is drawn by surface tension and wetting forces down onto the under lying wires that a fine, sponge-like network of 3-DV is formed.

Example 15 The bottom side of the filigree of Example 14 is characterized as follows: Although the wires were resting on the graphite substrate, and only in loose and occasional contact with each other at the hub of the design, the natural forces of wetting impelled the molten (slushy) 3- DV material to spread around the wires, and in so doing, to raise the wires up and away from contact with the graphite and completely to coat the wires; moreover, having wetted two adjacent wires, the surface tension of the molten metal would tend to pull the wires together-in any case, on solidification the loose wires would have been securely brazed together. Thus great latitude is afforded the 3-DV manufacturer in placing wires and appliques loosely on the unwettable graphite substrate in any distribution and without any mutual contact, if this is desired, and still have assurance that all parts would be securely brazed together.

(Example 16 A 3DV plaque was made as follows:

3-DV charge:

300 grams 35 +90 mesh Al powder 100 grams 90 +150 mesh A1 powder 125 ml. polyisobutylene Substrate: Copper Process:

Essentially as outlined in FIGS. 5 and 6 with following specifics In order to develop relatively large and high nubbly regions with a silvery-white color, no wetting agent nor any subsequent interdiffusion heat treatment was employed.

10 minutes at 871 C. (1600 F.).

0.100" thick.

Wire brushed.

Example 17 A 3-DV plaque was made as follows:

BROADENING STATEMENT It will be clear from studying the preceding disclosure that an inherent aspect of our invention is such a wide range of heterogeneous metallurgical structures which is correspondingly difficult to define and limit in precise terms that it will doubtless become evident to others skilled in the art how to apply the teachings of this disclosure to meet particular needs and individual whims and thereby to develop variations and modifications to obtain all or part of the benefits of our invention while seemingly to avoid a strict interpretation of the claims. We therefore claim all such insofar as they fall within the reasonable spirit and scope of our claims.

What is claimed is:

1. A process for producing a decoratively textured, metallurgical product, said process comprising the steps of:

(a) spreading a particulate refractory material in contact with a substrate of large area and with a first metal in a form having large surface area and a second metal in a form having large surface area, the melting point of said first metal being lower than the melting point of said second metal, said particulate refractory material being non wettable by said first metal, said particulate refractory material having an aver-age diameter ranging from 400 mesh to 4 inch;

(b) heating in a non-oxidizing atmosphere to a temperature at which said first metal melts to wet said second metal and by which said refractory material controls flow without total immersion in said first metal;

(0) cooling so as to produce a textured matrix; and

(d) mechanically removing said particulate refractory material from said matrix to leave a decoratively textured composite as a remainder.

2. The process of claim 1] wherein said second metal in step (a) is particulate.

3. The process of claim 1 wherein said second metal in step (a) is present in the composition of said substrate.

4. The process of claim 1 wherein said second metal in step (a) is present as a coating on said substrate.

5. The process of claim 1 wherein said temperature of step (b) is between said melting point of said first metal and said melting point of said second metal.

6. The process of claim wherein said substrate has an iron base composition.

7. The process of claim 1 wherein substrate is composed of a refractory material that is imcompatible with said first metal and that finally is separated from said decoratively textured composite.

8. The process of claim 1 wherein said heating of step (b) is continued for a period not long enough for the achievement of equilibrium.

9. The process of claim 1 wherein said heating of step (b) is continued for a period long enough for the achievement of equilibrium.

10. The process of claim 1 wherein said non-oxidizing atmosphere is selected from the class consisting of reducing gases and inert gases.

11. A process of producing a decoratively textured, metallurgical product, said process comprising the steps of:

(a) spreading a mixture of a copper compatible, particulate, fusible metal and an incompatible, particulate refractory material in contact with particulate copper throughout a large substrate area said fusible metal being wetting with respect to said copper and non wetting with respect to said particulate refractory material, said particulate refractory material having an average diameter ranging from 400 mesh to /4 inch;

(b) heating in a non-oxidizing atmosphere to a temperature at which said fusible metal melts to produce an alloy with said copper and 'by which said refractory material controls flow without total immersion in said metal, said fusible metal ranging from 2 to 45% by total weight of said alloy;

(0) cooling before said alloy reaches equilibrium so as to produce a textured matrix having a plurality of metallurgical phases; and

(d) mechanically removing said particulate refractory material from said matrix to leave a decoratively textured composite as a remainder.

12. The process of claim 11 wherein said copper in step (a) is present as a coating on said substrate.

13. The process of claim 11 wherein said fusible metal is selected from the class consisting of aluminum and tin.

14. The process of claim 11 wherein said substrate has an iron base composition.

15. The process of claim 11 wherein substrate is composed of a refractory material that is incompatible with said fusible metal and that finally is separated from said decoratively textured components.

16. The process of claim 11 wherein said temperature of step (b) ranges from 1382 to 1562 17. The process of claim 11 wherein said non-oxidizing atmosphere has a dew point lower than C.

18. The process of claim 11 wherein said substrate is reticulated.

19. The process of claim 11 wherein said plurality of metallurgical phases are selected from the following: alpha copper solid solution, gamma-2 intermetallic compound, delta intermetallic compound, zeta-2 intermetallic compound, eta-2 intermetallic compound, theta, and alpha aluminum solid solution.

20. The process of claim 11 wherein said refractory material of step (a) is a metal oxide.

21. A process for producing a decoratively textured metallurgical product, said process comprising the steps of: (a) spreading a mixture of a copper compatible, particulate fusible metal and an incompatible, particulate refractory material in contact with particulate copper throughout a large substrate area, said particulate refractory material being non-wettable by said fusible metal and said copper being wettable by said fusible metal, said particulate refractory material having an average diameter ranging from 400 mesh to A in; (b) heating in a non-oxidizing atmosphere to a temperature at which said fusible metal melts to produce an alloy with said copper and by which said refractory material controls flow without total immersion in said metal, said fusible metal ranging from 2 to 45% by weight of said alloy; (0) cooling before said alloy reaches equilibrium so as to produce a textured matrix having a plurality of metallurgical phases; and (d) mechanically removing said particulate refractory material from said matrix to leave a decoratively textured composite as a remainder, said fusible metal being selected from the class consisting of aluminum and tin, said temperature of said step (b) ranging from 1382 F. to 1562" F., said non-oxidizing atmosphere being selected from the class consisting of reducing and inert gases.

22. A process for producing a decoratively textured metallurgical product, said process comprising the steps of: (a) spreading a mixture of a copper compatible, particulate, fusible metal and an incompatible, particulate refractory material composed of aluminum oxide and an organic binder containing a halide flux in contact with copper throughout a large substrate area in a relatively thin film said particulate refractory material being non wettable by said fusible metal and said copper being wettable by said fusible metal, said particulate refractory material having an average diameter ranging from 400 mesh to /1 inch; (b) heating in a non-oxidizing atmosphere to a temperature at which said fusible metal melts to produce an alloy with said copper and by which said refractory material controls flow without total immersion in said metal, said fusible metal ranging from 2 to by total weight of said alloy; (0) cooling before said alloy reaches equilibrium so as to produce a textured matrix having a plurality of metallurgical phases; and ((1) mechanically removing said particulate refractory material from said matrix to leave a decoratively textured composite as a remainder, said fusible metal being selected from the class consisting of aluminum and tin, said temperature of said step (b) ranging from 750C. to 850 C., said refractory-material of step (a) being composed of particles having an average diameter ranging from 400 mesh to inch, said non-oxidizing atmosphere being selected from the class consisting of reducing and inert gases.

References Cited UNITED STATES PATENTS 2,775,531 12/1956 Montgomery et al. ll722 2,323,169 6/ 1943 Wagenhals 117-22 2,694,647 11/1954 Cole 117-22 2,339,108 l/ 1944 Vander Pyl ll722X RALPH S. KENDALL, Primary Examiner U.S. Cl. X.R. 

